Those familiar with high pressure blasting equipment commonly used in the surface cleaning and material cutting businesses have long desired a cost effective high pressure pump for providing higher pressure to the blasting gun. In most high pressure blasting applications, the fluid pump must be portable since the surfaces to be cleaned or the material to be cut cannot practically be transported to a stationary pump site. In the cleaning industry, blasting gun operators have long recognized the enhanced effectiveness of water blasting at a fluid pressure of 15,000 PSI compared to water blasting at 10,000 PSI. These individuals have also recognized that a system capable of reliably delivering fluid pressures in excess of 30,000 PSI would be markedly more effective for cleaning purposes, and in many instances would replace sand blasting operations. Those involved in using high fluid pressure for cutting operations similarly recognize that high pressure equipment for cutting, for example, reinforced concrete, would be much more efficient if the fluid system which delivered water to the cutting gun could reliably operate at 35,000 PSI compared to 15,000 PSI.
High pressure pumps employing a plurality of plungers and an in-line valve design as disclosed in U.S. Pat. No. 4,551,077 has been successfully used for generating pressures in excess of 15,000 PSI. U.S. Pat. No. 5,302,087 discloses a technique for loading the pump compression rods which reliably seal the suction manifold with both the upstream plunger housing and the downstream discharge housing, thereby reducing leakage and facilitating pump maintenance and repair.
Those skilled in the design and engineering of high pressure pumps have long recognized that significant problems must be overcome to provide a cost effective high pressure pump capable of outputting 30,000 PSI or more. Numerous problems which are either absent or have little effect in the design, manufacture, and operation of a 15,000 PSI pump become critical to the successful operation of a pump capable of delivering 30,000 PSI or more. At these high pressures, the compressibility of water and its effect on pump efficiency must be considered, and accordingly the size of the fluid chamber containing compressed fluid between the plunger at the end of its pumping stroke and the discharge check valve must be limited. Efforts are accordingly undertaken to reducing this "dead zone" chamber, but in many cases such techniques are contrary to the life of the pump and require increased pump maintenance.
As the pressure output for the fluid pump increases, pump parts become more susceptible to galling and to reduced life due to elevated fluid temperatures. The temperature of compressed water increases approximately 3.degree. F. per thousand PSI, and accordingly water supplied to the inlet of the pump at 80.degree. F. reaches a temperature in excess of 180.degree. F. while within the pump, thereby adversely effecting the life of seals and contributing to galling of metal pump components.
Although numerous obstacles are encountered developing a reliable high pressure pump capable of delivery pressures of approximately 35,000 PSI to blasting equipment, businesses using such pumps for cleaning or cutting operations have long desired such a pump. The improved high pressure pump as hereafter disclosed will have significant benefits for those involved in the blasting operations. The portable high pressure pump of the present invention is highly reliable, and is able to deliver fluid pressure in excess of 35,000 PSI to the blasting or cutting gun.